664256844 has 72 divisors (see below), whose sum is σ = 1811496960. Its totient is φ = 204452352.

The previous prime is 664256837. The next prime is 664256851. The reversal of 664256844 is 448652466.

664256844 is a `hidden beast` number, since 6 + 6 + 42 + 568 + 44 = 666.

664256844 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (664256837) and next prime (664256851).

It is a self number, because there is not a number n which added to its sum of digits gives 664256844.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22197 + ... + 42675.

It is an arithmetic number, because the mean of its divisors is an integer number (25159680).

Almost surely, 2^664256844 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664256844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (905748480).

664256844 is an abundant number, since it is smaller than the sum of its proper divisors (1147240116).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664256844 is a wasteful number, since it uses less digits than its factorization.

664256844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20559 (or 20554 counting only the distinct ones).

The product of its digits is 1105920, while the sum is 45.

The square root of 664256844 is about 25773.1807117399. The cubic root of 664256844 is about 872.5266069067.

The spelling of 664256844 in words is "six hundred sixty-four million, two hundred fifty-six thousand, eight hundred forty-four".